//元素加载完毕之后触发
window.onload = function(){
var box = document.getElementsByClassName("box")[0];
box.onmouseover = function(){
	box.style.background = "deepskyblue";
	box.innerHTML = "帅逼";
	this.style.borderRadius = "50%";
	this.style.transition = "2s";
	this.style.lineHeight = "500px";
	this.style.textAlign = "center";
	this.style.fontSize = "36px";
		
	
	}
	box.onmouseout = function(){
		this.style.background = "pink";
		box.innerHTML = "丑比";
		this.style.borderRadius = "0";
		this.style.transition = "2s";
		this.style.lineHeight = "500px";
		this.style.textAlign = "center";
	}
}